With rapid progress of the technology of compressing moving pictures and voice data, the high-speed data transmission technology using XDSL, optical fiber, etc., and widespread infrastructures, streaming replay for sequentially replaying moving picture data and voice data on a server on the Internet (hereinafter referred to as streaming contents) while receiving the data over the network has made remarkable progress. In the streaming replay, a user can enjoy the streaming contents on the server at any time.
On the other hand, as a broadcast system, a system of transmitting a program digest through a unicast at a request from a user on the sending side, and starting receiving program data transmitted through a broadcast after the transmission of the digest in the receiving side has been proposed (Japanese Patent Application Laid-open No. 2002-118553).
There is also a system proposed for a case in which, when replaying of a recorded portion of contents is started while the contents are being recorded, the time to replay the recorded portion is shortened, and when the replaying of the recorded portion is finished, control is switched to replay the contents being broadcast (Japanese Patent Application Laid-open No. 2000-339857).
When one of two pieces of image data which are related to each other is replayed and the other piece of image data is consecutively replayed thereafter, changeover from the former image to the latter image may not be performed smoothly, which may disturb a viewer to enjoy the images.